Solubility parameter estimation and phase inversion modeling of bentonite-doped polymeric membrane systems

Effects of bentonite concentration on morphology and permeation characteristics of bentonite-doped polysulfone membranes were investigated. Solubility sphere for bentonite was constructed to estimate its solubility parameter. Thermodynamic modeling of phase inversion of this system was carried out using Flory–Huggins theory. The trade-off between thermodynamic and kinetic parameters was used to predict the membrane morphology for bentonite concentration varying from 0 to 5 wt %. The porosity of bentonite-doped membranes decreased up to 3 wt % that increased thereafter. Morphological analysis showed dense cross section with finger-like macrovoids at 3 wt % beyond which it changed to honeycomb structure with large circular voids. Permeability of 3 wt % membrane was the lowest (5.6 × 10⁻¹² m/Pa s) with 95% bovine serum albumin rejection. Contact angle of the membranes decreased from 83 to 66° with bentonite addition making the membrane more hydrophilic. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48450.     

Effect of irradiation on the proteinase inhibitor activity and digestibility (in vitro) of safflower oilcake

Trypsin and chymotrypsin inhibitor activities of safflower oilcake were studied before and after irradiation. The various doses to which samples were exposed ranged from 7 Gy to 10 kGy. The trypsin inhibitor is inactivated at 42 Gy, whereas the chymotrypsin inhibitor remains active, even at the much higher dose of 10 kGy. Thein vitro digestibility values also showed a significant improvement after irradiation. Exposure to a low dose of 42 Gy is sufficient to improve the nutritional value of the oilcake.     

Design and performance analysis of MEMS capacitive pressure sensor array for measurement of heart rate

Microsystem Technologies - In this paper, a diaphragm based MEMS capacitive pressure sensor array in conjunction with signal conditioning circuitry is designed for measuring Heart Rate (HR) of...     

3D Oxidized Graphene Frameworks: An Efficient Adsorbent for Methylene Blue

Extraordinary properties of graphene and its derivatives have found application in varied areas such as energy, electronics, optical devices and sensors, to name a few. Large surface area along with specialized functional groups make these materials attractive for removal of dye molecules in solution via adsorption. Industrial effluents contain large amounts of toxic chemicals resulting in pollution of water bodies, which pose environmental hazards in general. Here we report application of 3D oxidized graphene frameworks in the efficient removal of cationic dye molecules such as methylene blue via adsorption. Systematic parametric studies investigating the effect of the initial dye concentration, pH and contact time have been performed. Spectroscopic analysis of the filtrate suggests that tortuous paths in 3D oxidized graphene frameworks result in efficient removal of dye molecules due to enhanced interaction. The hydroxyl groups retained in these 3D oxidized graphene frameworks facilitate adsorption of the dye molecules while passing through the adsorbent. pH studies suggest that maximum removal efficiency for methylene blue was achieved at pH value of 9. The results suggest that these 3D oxidized graphene frameworks can be used for purification of large volumes of contaminated water from cationic dyes in waste water treatment plants.     

Protease inhibitors and in vitro digestibility of karanja (Pongamia glabra) oil seed residue. A comparative study of various treatments

Trypsin and chymotrypsin inhibitor activities (TIA and CIA) were assayed before and after processing of Karanja oil seed residue. Upon treatment, the loss of TIA and CIA varied with the type of processing or extraction: the reduction after solvent extraction ranged between 34 and 15%, respectively. These activities were completely removed in 2.4% HCl; 83.35 and 54.86% were removed on autoclaving; 33.86 and 15.30% on fermentation; and removal was 4.36–83.69% and 3.66–77.59% after exposure to different doses of gamma radiation (1, 5, 10, and 50 KGy). An in vitro digestibility study was carried out to confirm the inactivation of the inhibitors and showed improvements from 45 to 81%, with the maximum observed in 2.4% HCl solvent-refluxed residue. A linear relationship was observed between the reduction in protease inhibitor activities and the improvement in digestibility.     

Study of dielectric properties of leukocytes for the determination of malignancy by capacitive type MEMS sensor

Microsystem Technologies - The present work deals with a non-clinical scheme to develop a system-on-chip for the detection and identification of the malignant cells in a known volume of white blood...     

Development and performance analysis of a low-cost MEMS microphone-based hearing aid with three different audio amplifiers

In this paper, MEMS-based capacitive microphone and low-cost amplifier are designed for low-cost power-efficient hearing aid application. The developed microphone along with the associated circuitry is mounted on a common board in the form of pocket-type (body-worn) device. The designed microphone consists of a flexible circular silicon nitrite (Si₃N₄) diaphragm and a polysilicon-perforated back plate with air as dielectric between them. The incident acoustic waves on the sensor cause deflection of the diaphragm to alter the air gap between the perforated back plate (fixed electrode) and the diaphragm (moving plate) which causes a change in capacitance. The acoustic pressure applied to the microphone is from 0 to 100 Pa for an operating range of 100 Hz–10 kHz which corresponds to the audible frequency range in case of human beings. The main purpose of this work is to increase the longevity of battery used in conventional hearing aids. The designed MEMS microphone with Si₃N₄ diaphragm is capable of identifying acoustic frequencies (100 Hz to 10 kHz) which correspond to a specific change in absolute pressure from 0 to 100 Pa for 2-micron-thick diaphragm with a sensitivity of about 0.08676 mV/Pa. The design of the sensor and the characteristics analysis are performed in FEM-based simulation software, which are later validated in real time. The prototype is designed using MEMS microphone and low-cost amplifier ICs with biasing components in the form of pocket-type (body-worn) hearing aid. In order to study the performance of proposed device, three different market-available amplifiers with controllable gain are used. Finally, the performance of the hearing aid is studied through audio spectrogram analysis to choose the best-suited amplifier among the three.